The present invention relates to the interconnection of an optical fiber and an optical device in predetermined alignment. As used herein the term "optical device" means optical fiber, lens, coupler or the like.
One of the difficult problems associated with implementing an optical fiber system involves the interconnection of the fiber with other optical devices. Present techniques often involve fusion splicing as well as the use of various adhesives in order to firmly hold the component parts together. This however assumes that proper alignment of the light propagating region of the optical fiber has been accomplished. Proper alignment is generally accomplished in one of two ways. Active alignment can be accomplished by propagating a light beam through the system and actively positioning the components to be connected so as to maximize the transmitted power. The pieces are then permanently bonded either directly to one another or to other reference pieces. This technique requires the ability to inject light into the system, a task which is often difficult, particularly in field installations. Further, the precision of the movements required to accomplish the alignment is very high, thus requiring expensive and delicate equipment. An added complication is that during the bonding operation the alignment is often disrupted. For example, adhesive materials can creep during curing, and during fusing operations, surface tension can distort alignment. Problems are also encountered with thermal cycling of the connections, particularly when adhesives are used having much different thermal expansion coefficients than the glass components.
A second alternative is to use the outside surface of the fiber and components as a reference and to position the pieces in V-grooves, channels and the like. This technique works acceptably well for components of the same outside size and shape, eg. fiber-to-fiber. With the disparity of sizes and shapes of many components this technique most likely will not work in all cases.